1. Field of the Invention
An embodiment of the present invention is related to a digital watermark embedding device, a digital watermark detecting device, a digital watermark embedding method, a digital watermark detecting method, a computer-readable recording medium containing a digital watermark embedding program, and a computer-readable recording medium containing a digital watermark detecting program.
2. Description of the Related Art
In the voice signal processing technology in recent years, it has become possible to synthesize various voices. However, it also involves risks such as impersonation with the voice of an acquaintance using the synthesized voice or misuse of the voice of a notable public figure. In order to prevent such crimes from occurring, there has been a demand for embedding additional information in a synthesized voice, and detecting any misuse. For example, examples of a known method of embedding additional information include a method of embedding a digital watermark using the acoustic masking phenomenon and a method of embedding a digital watermarking while disguising it as quantization noise. Moreover, a method is also known in which an additional information signal is embedded in the frequency amplitude characteristics of the spectral distribution of voice data.
However, during a conversion over a land-line phone or a cellular phone, because of codec distortion occurring with respect to the original voice, the embedded watermark becomes prone to disappearing, thereby making it difficult to detect the additional information.
Therefore, there is a need for an embedding device and a detecting device that enable embedding and detection of a digital watermark having resistance against various distortions and being excellent in maintaining the confidentiality of additional information with respect to the voice of the land-line phone or the cellular phone.